Polyolefins such as high density polyethylene (HDPE) homopolymer and linear low density polyethylene (LLDPE) copolymer can be produced using various combinations of catalyst systems and polymerization processes. Chromium-based catalyst systems can, for example, produce olefin polymers having good extrusion processibility and polymer melt strength, typically due to their broad molecular weight distribution (MWD).
In some end-use applications, it can be beneficial to have the processibility and melt strength similar to that of an olefin polymer produced from a chromium-based catalyst system, as well as improvements in stress crack resistance (e.g., higher notched tensiles, lower natural draw ratios) at equal or higher polymer densities. Accordingly, it is to these ends that the present invention is directed.